Allow for animated horizontal viewport resizing when chart data increases or decreases

build.gradle

@@ -2,8 +2,20 @@
 buildscript {
     repositories {
         mavenCentral()
+        maven {
+            url 'https://maven.google.com/'
+            name 'Google'
+        }
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.1.0'
+        classpath 'com.android.tools.build:gradle:3.0.0'
     }
 }
+
+repositories {
+    maven {
+        url 'https://maven.google.com/'
+        name 'Google'
+    }
+}

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Apr 10 15:27:10 PDT 2013
+#Sun Nov 05 15:03:49 EST 2017
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=http\://services.gradle.org/distributions/gradle-2.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip

hellocharts-library/build.gradle

@@ -4,7 +4,7 @@ apply from: 'https://raw.github.com/chrisbanes/gradle-mvn-push/master/gradle-mvn
 
 //To upload to maven central
 //http://zserge.com/blog/gradle-maven-publish.html
-//gradle uploadArchives
+// gradle uploadArchives
 
 buildscript {
     repositories {
@@ -60,6 +60,7 @@ android {
         abortOnError false
     }
 
+    buildToolsVersion '26.0.2'
 }
 
 //Execute "gradle clean jarRelease" to cook jar.

hellocharts-library/src/lecho/lib/hellocharts/model/AbstractChartData.java

@@ -18,6 +18,8 @@ public abstract class AbstractChartData implements ChartData {
     protected int valueLabelTextSize = DEFAULT_TEXT_SIZE_SP;
     protected Typeface valueLabelTypeface;
 
+    protected int lastDataSize, newDataSize;
+
     /**
      * If true each value label will have background rectangle
      */
@@ -163,4 +165,16 @@ public void setValueLabelBackgroundColor(int valueLabelBackgroundColor) {
         this.valueLabelBackgroundColor = valueLabelBackgroundColor;
     }
 
+    public int getLastDataSize() {
+        return lastDataSize;
+    }
+
+    public int getNewDataSize() {
+        return newDataSize;
+    }
+
+    public void finish() {
+        lastDataSize = newDataSize;
+    }
+
 }

hellocharts-library/src/lecho/lib/hellocharts/model/ColumnChartData.java

@@ -22,6 +22,7 @@ public ColumnChartData() {
 
     public ColumnChartData(List<Column> columns) {
         setColumns(columns);
+        setLastDataSize();
     }
 
     /**
@@ -35,6 +36,7 @@ public ColumnChartData(ColumnChartData data) {
         for (Column column : data.columns) {
             this.columns.add(new Column(column));
         }
+        setLastDataSize();
     }
 
     public static ColumnChartData generateDummyData() {
@@ -67,6 +69,7 @@ public void finish() {
         for (Column column : columns) {
             column.finish();
         }
+        super.finish();
     }
 
     public List<Column> getColumns() {
@@ -79,6 +82,7 @@ public ColumnChartData setColumns(List<Column> columns) {
         } else {
             this.columns = columns;
         }
+        setLastDataSize();
         return this;
     }
 
@@ -134,4 +138,12 @@ public ColumnChartData setBaseValue(float baseValue) {
         return this;
     }
 
+    public void setLastDataSize() {
+        lastDataSize = columns.size();
+    }
+
+    public int setNewDataSize() {
+        return newDataSize = columns.size();
+    }
+
 }

hellocharts-library/src/lecho/lib/hellocharts/model/LineChartData.java

@@ -18,6 +18,7 @@ public LineChartData() {
 
     public LineChartData(List<Line> lines) {
         setLines(lines);
+        setLastDataSize();
     }
 
     /**
@@ -30,6 +31,7 @@ public LineChartData(LineChartData data) {
         for (Line line : data.lines) {
             this.lines.add(new Line(line));
         }
+        setLastDataSize();
     }
 
     public static LineChartData generateDummyData() {
@@ -59,6 +61,7 @@ public void finish() {
         for (Line line : lines) {
             line.finish();
         }
+        super.finish();
     }
 
     public List<Line> getLines() {
@@ -71,6 +74,7 @@ public LineChartData setLines(List<Line> lines) {
         } else {
             this.lines = lines;
         }
+        setLastDataSize();
         return this;
     }
 
@@ -89,4 +93,20 @@ public LineChartData setBaseValue(float baseValue) {
         this.baseValue = baseValue;
         return this;
     }
+
+    public void setLastDataSize() {
+        int size = 0;
+        for (Line line : lines) {
+            size = line.getValues().size() > size ? line.getValues().size() : size;
+        }
+        lastDataSize = size;
+    }
+
+    public void setNewDataSize() {
+        int size = 0;
+        for (Line line : lines) {
+            size = line.getValues().size() > size ? line.getValues().size() : size;
+        }
+        newDataSize = size;
+    }
 }

hellocharts-library/src/lecho/lib/hellocharts/renderer/BubbleChartRenderer.java

@@ -100,6 +100,11 @@ public void onChartDataChanged() {
 
     @Override
     public void onChartViewportChanged() {
+        onChartViewportChanged(1);
+    }
+
+    @Override
+    public void onChartViewportChanged(float scale) {
         if (isViewportCalculationEnabled) {
             calculateMaxViewport();
             computator.setMaxViewport(tempMaximumViewport);

hellocharts-library/src/lecho/lib/hellocharts/renderer/ChartRenderer.java

@@ -16,6 +16,8 @@ public interface ChartRenderer {
 
     public void onChartViewportChanged();
 
+    public void onChartViewportChanged(float scale);
+
     public void resetRenderer();
 
     /**

hellocharts-library/src/lecho/lib/hellocharts/renderer/ColumnChartRenderer.java

@@ -87,8 +87,13 @@ public void onChartDataChanged() {
 
     @Override
     public void onChartViewportChanged() {
+        onChartViewportChanged(1);
+    }
+
+    @Override
+    public void onChartViewportChanged(float scale) {
         if (isViewportCalculationEnabled) {
-            calculateMaxViewport();
+            calculateMaxViewport(scale);
             computator.setMaxViewport(tempMaximumViewport);
             computator.setCurrentViewport(computator.getMaximumViewport());
         }
@@ -125,12 +130,14 @@ public boolean checkTouch(float touchX, float touchY) {
         return isTouched();
     }
 
-    private void calculateMaxViewport() {
+    private void calculateMaxViewport(float scale) {
         final ColumnChartData data = dataProvider.getColumnChartData();
+        int diff = data.setNewDataSize() - data.getLastDataSize();
+        float right = (data.getNewDataSize() - diff) + diff * scale - 0.5f;
         // Column chart always has X values from 0 to numColumns-1, to add some margin on the left and right I added
         // extra 0.5 to the each side, that margins will be negative scaled according to number of columns, so for more
         // columns there will be less margin.
-        tempMaximumViewport.set(-0.5f, baseValue, data.getColumns().size() - 0.5f, baseValue);
+        tempMaximumViewport.set(-0.5f, baseValue, right, baseValue);
         if (data.isStacked()) {
             calculateMaxViewportForStacked(data);
         } else {

hellocharts-library/src/lecho/lib/hellocharts/renderer/ComboChartRenderer.java

@@ -37,10 +37,15 @@ public void onChartDataChanged() {
 
     @Override
     public void onChartViewportChanged() {
+        onChartViewportChanged(1);
+    }
+
+    @Override
+    public void onChartViewportChanged(float scale) {
         if (isViewportCalculationEnabled) {
             int rendererIndex = 0;
             for (ChartRenderer renderer : renderers) {
-                renderer.onChartViewportChanged();
+                renderer.onChartViewportChanged(scale);
                 if (rendererIndex == 0) {
                     unionViewport.set(renderer.getMaximumViewport());
                 } else {

hellocharts-library/src/lecho/lib/hellocharts/renderer/LineChartRenderer.java

@@ -88,10 +88,14 @@ public void onChartDataChanged() {
         onChartViewportChanged();
     }
 
-    @Override
     public void onChartViewportChanged() {
+        onChartViewportChanged(1);
+    }
+
+    @Override
+    public void onChartViewportChanged(float scale) {
         if (isViewportCalculationEnabled) {
-            calculateMaxViewport();
+            calculateMaxViewport(scale);
             computator.setMaxViewport(tempMaximumViewport);
             computator.setCurrentViewport(computator.getMaximumViewport());
         }
@@ -172,28 +176,31 @@ public boolean checkTouch(float touchX, float touchY) {
         return isTouched();
     }
 
-    private void calculateMaxViewport() {
-        tempMaximumViewport.set(Float.MAX_VALUE, Float.MIN_VALUE, Float.MIN_VALUE, Float.MAX_VALUE);
+    /**
+     by setting the tempMaximumViewport after the new points of the viewport are calculated,
+     it doesn't cause the small movement in the viewport directly before animating the horizontal axis
+     */
+    private void calculateMaxViewport(float scale) {
         LineChartData data = dataProvider.getLineChartData();
-
+        float maxX = Float.MIN_VALUE, maxY = Float.MIN_VALUE, minX = Float.MAX_VALUE, minY = Float.MAX_VALUE;
         for (Line line : data.getLines()) {
             // Calculate max and min for viewport.
             for (PointValue pointValue : line.getValues()) {
-                if (pointValue.getX() < tempMaximumViewport.left) {
-                    tempMaximumViewport.left = pointValue.getX();
-                }
-                if (pointValue.getX() > tempMaximumViewport.right) {
-                    tempMaximumViewport.right = pointValue.getX();
-                }
-                if (pointValue.getY() < tempMaximumViewport.bottom) {
-                    tempMaximumViewport.bottom = pointValue.getY();
-                }
-                if (pointValue.getY() > tempMaximumViewport.top) {
-                    tempMaximumViewport.top = pointValue.getY();
-                }
-
+                maxX = pointValue.getX() > maxX ? pointValue.getX() : maxX;
+                maxY = pointValue.getY() > maxY ? pointValue.getY() : maxY;
+                minX = pointValue.getX() < minX ? pointValue.getX() : minX;
+                minY = pointValue.getY() < minY ? pointValue.getY() : minY;
             }
         }
+        tempMaximumViewport.set(minX, maxY, maxX, minY);
+        data.setNewDataSize();
+        int diff = data.getNewDataSize() - data.getLastDataSize();
+        float scaleFactor;
+        if (diff != 0 ) {
+            scaleFactor = diff > 0 ? 1.1f : 1.0f;
+            tempMaximumViewport.right -= diff;
+            tempMaximumViewport.right += diff * scaleFactor * scale;
+        }
     }
 
     private int calculateContentRectInternalMargin() {

hellocharts-library/src/lecho/lib/hellocharts/renderer/PieChartRenderer.java

@@ -133,6 +133,11 @@ public void onChartDataChanged() {
 
     @Override
     public void onChartViewportChanged() {
+        onChartViewportChanged(1);
+    }
+
+    @Override
+    public void onChartViewportChanged(float scale) {
         if (isViewportCalculationEnabled) {
             calculateMaxViewport();
             computator.setMaxViewport(tempMaximumViewport);

hellocharts-library/src/lecho/lib/hellocharts/view/AbstractChartView.java

@@ -149,7 +149,7 @@ public void cancelDataAnimation() {
     @Override
     public void animationDataUpdate(float scale) {
         getChartData().update(scale);
-        chartRenderer.onChartViewportChanged();
+        chartRenderer.onChartViewportChanged(scale);
         ViewCompat.postInvalidateOnAnimation(this);
     }
 

hellocharts-samples/build.gradle

@@ -3,6 +3,7 @@ apply plugin: 'com.android.application'
 dependencies {
     //compile fileTree(dir: 'libs', include: '*.jar')
     compile project(':hellocharts-library')
+    //noinspection GradleCompatible
     compile 'com.android.support:support-v4:23.3.0'
     compile 'com.android.support:appcompat-v7:23.3.0'
 }
@@ -34,15 +35,16 @@ android {
             assets.srcDirs = ['assets']
         }
     }
-	
-	buildTypes {
-		release {
+
+    buildTypes {
+        release {
             minifyEnabled false
-			proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
-		}
-	}
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
 
-	lintOptions {
-		abortOnError false
-	}
+    lintOptions {
+        abortOnError false
+    }
+    buildToolsVersion '26.0.2'
 }